1. Field of the Invention
The present invention provides a connecting structure of a coaxial cable and a coaxial connector.
2. Description of the Related Art
A conventional connecting structure of a coaxial cable and a coaxial connector electrically and mechanically connects a coaxial cable and a coaxial connector. A braided conductor is exposed at an end of the coaxial cable. Connecting conductor portions formed continuously from an end of a shell (for example, a grounded shell) of the coaxial connector are inserted into a space between the braided conductor and a metal tape conductor (or a dielectric material) inside the braided conductor. Then, a cylindrical sleeve is caulked.
Conventional examples of the outside contours of the cross section of the caulked sleeve 4 are shown in FIGS. 12-14. FIG. 12 shows an outside contour 101 of the cross section of the caulked sleeve 4 formed into an almost hexagonal shape (type 1); FIG. 13 shows an outside contour 102 of the cross section of the caulked sleeve 4 formed into an almost elliptical shape (type 2); and FIG. 14 shows an outside contour 103 of the cross section of the caulked sleeve 4 which is shaped like a letter O (type 3).
However, it is difficult to have sufficient tensile strength and high-frequency performance at the same time using the conventional examples of a caulked sleeve 4 as shown in FIGS. 12-14.
For example, when the outside contour of the cross section of the caulked sleeve 4 is shaped as shown in FIG. 12, 13, or 14, the VSWR (Voltage Standing Wave Ratio) deteriorates when the tensile strength is a certain value. In the conventional examples of FIGS. 12-14, this problem occurs since the contours of the cross sections of the dielectric material and the external conductor, which surround the central conductor of the coaxial cable, deform from their original concentric circular shapes. This deformation occurs at a higher degree as the tensile strength increases.
In view of the foregoing problems, the present invention provides a connecting structure of a coaxial cable and a coaxial connector, which can have sufficient tensile strength and high-frequency performance at the same time.
Extensive experiments have been conducted repetitively to be able to set tensile strength to a certain value while preventing deterioration of high-frequency performance in a connecting structure of a coaxial cable and a coaxial connector by forming the contour of a cross section of a dielectric material 12 and an exterior conductor, which surround a central conductor 11 of a coaxial cable 1, into an almost concentric shape. It was discovered that both of the respective desired ranges of tensile strength and high-frequency performance can be achieved when an outside contour 5 of a cross section of the caulked sleeve 4 having a crimp height H1 is formed into an almost circular shape by jointing two opposing almost semi-circular members 43. An outside contour of each of the two opposing almost semi-circular members 43 has a radius R1 so that R1 and H1 satisfy Equations (1) and (2), respectively:
R1=P1xc3x97(D+2xc3x97T1) andxe2x80x83xe2x80x83(1)
H1=P2xc3x97R1xe2x80x83xe2x80x83(2)
where D is an outside diameter of the coaxial cable 1, T1 as a plate thickness of the sleeve 4, P1 is a numerical value set within the range from 0.45 to 0.48, and P2 is a numerical value set within the range from 2.02 to 2.12.
The present invention provides a connecting structure of a coaxial cable and a coaxial connector that electrically and mechanically connects a coaxial cable 1 and a coaxial connector 2. In an embodiment of the present invention, an exterior conductor of the coaxial cable 1 comprises a braided conductor 14 and a metal tape conductor 13 that is located inside the braided conductor 14. The braided conductor 14 is exposed at an end of the coaxial cable 1. Connecting conductor portions 26 formed continuously at an end of a shell 21 of the coaxial connector 2 are inserted into a space between the braided conductor 14 and the metal tape conductor 13. Then, the cylindrical sleeve 4 is caulked. An outside contour 5 of a cross section of the caulked sleeve 4 is formed into an almost circular shape having a crimp height H1 by jointing two opposing almost semi-circular members 43. An outside contour of each of the two opposing almost semi-circular members 43 has a radius R1 so that R1 and H1 satisfy Equations (1) and (2) above, respectively, where D is an outside diameter of the coaxial cable 1 and T1 is a plate thickness of the sleeve 4.
According to this embodiment of the present invention, the exterior conductor of the coaxial cable 1 comprises the braided conductor 14 and the metal tape conductor 13. The outside contour 5 of the cross section of the caulked sleeve 4 is formed into an almost circular shape having the crimp height H1 by jointing two opposing almost semi-circular members 43. The outside contour of each of the two opposing almost semi-circular members 43 has the radius R1 so that R1 and H1 satisfy Equations (1) and (2) above, respectively. Therefore, deterioration of high-frequency performance can be prevented without sacrificing tensile strength, and the respective desired ranges of both tensile strength and high-frequency performance can be achieved.
In another embodiment of the present invention, a connecting structure of a coaxial cable and a coaxial connector for electrically and mechanically connecting a coaxial cable 1 and a coaxial connector 2 is provided. The coaxial cable 1, according to this embodiment of the present invention, comprises an exterior conductor which only comprises a braided conductor 14. A dielectric material 12 is located inside the braided conductor 14. The braided conductor 14 is exposed at an end of the coaxial cable 1, and connecting conductor portions 26 formed continuously at an end of a shell 21 of the coaxial connector 2 are inserted into a space between the braided conductor 14 and the dielectric material 12. Then, the cylindrical sleeve 4 is caulked. Therefore, an outside contour 5 of a cross section of the caulked sleeve 4 is formed into an almost circular shape having a crimp height H1 by jointing two opposing almost semi-circular members 43. An outside contour of each of the two opposing almost semi-circular members 43 has a radius R1 so that R1 and H1 satisfy Equations (1) and (2) above, respectively, where D is an outside diameter of the coaxial cable 1 and T1 is a plate thickness of the sleeve 4.
In the connecting structure of the coaxial cable 1 and the coaxial connector 2 according to this embodiment of the present invention in which the exterior conductor of the coaxial cable 1 comprises the braided conductor 14 alone, the outside contour 5 of the cross section of the caulked sleeve 4 is arranged in the same manner as the outside contour 5 of the cross section of the caulked sleeve 4 according to the embodiment of the present invention in which the exterior conductor of the coaxial cable 1 comprises the braided conductor 14 and the metal tape conductor 13. Therefore, deterioration of high-frequency performance can be prevented without sacrificing tensile strength while being able to achieve the respective desired ranges of both tensile strength and high-frequency performance.
Another embodiment of the present invention provides the connecting structure of a coaxial cable and a coaxial connector according to any of the embodiments described above. Furthermore, an outside contour of a cross section of a joint portion 42 which connects each end of an outside contour of the cross section of the two opposing almost semi-circular members 43, which each have the radius R1, to an outside contour 51 of a cross section of protruding strips 41 on an outer circumference of the caulked sleeve 4. Thus, R2 is a curvature radius of the outside contour of the cross section of the joint portion 42 between the outside contour 51 of the cross section of the protruding strips 41 and each end of the outside contour of the cross section of the almost semi-circular members 43 having the radius R1. Additionally, H2 is a height of the outside contour 51 of the cross section of the protruding strips 41 in the direction of a crimp height H1. In order to achieve the respective desired control ranges of both tensile strength and high-frequency performance in a stable manner, the curvature radius R2 and the height H2 satisfy Equations (3) and (4), respectively:
R2=P3xc3x97T1) andxe2x80x83xe2x80x83(3)
H2=P4xc3x97R1xe2x80x83xe2x80x83(4)
where P3 is a numerical value set within the range from 1.8 to 2.2 and P4 is a numerical value set within the range from 1.5 to 2.0.
According to this embodiment of the present invention, the outside contour of the cross section of the joint portion 42 connects each end of the outside contour of the cross section of the two opposing almost semi-circular members 43 having the radius R1 to the outside contour 51 of the cross section of the protruding strips 41 on the outer circumference of the caulked sleeve 4. The curvature radius R2 of the outside contour of the cross section of the joint portion 42 between the outside contour 51 of the cross section of the protruding strips 41 and each end of the outside contour of cross section of the almost semi-circular members 43 with the radius R1 satisfies Equation (3). Additionally, the height H2 of the outside contour 51 of the cross section of the protruding strips 41 in the direction of the crimp height H1 satisfies Equation (4). Thus, both tensile strength and high-frequency performance can be achieved in a stable manner within their respective desired ranges.